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TCRB (TRB) Breakapart

Catalogue Numbers
LPH 048-S (5 tests)
LPH 048 (10 tests)

Probe Specification

  • TCRB, 7q34, Red
  • TCRB, 7q34, Green

The TCRB product consists of a 177kb probe, labelled in red, covering the centromeric end of the TRB gene, including the D7S2473 marker and a green probe covering a 133kb region located telomeric to the TRB gene, including the SHGC-81465 marker.

Probe Information

Chromosomal translocations with breakpoints in beta T-cell receptor (TCR) gene loci at 7q34 are recurrent in several T-cell malignancies including T-cell acute lymphoblastic leukaemia (T- ALL)1.

T-cell acute lymphoblastic leukaemia (T-ALL) is an aggressive malignancy of the lymphoblasts committed to the T-cell lineage and represent 15% of childhood and 25% of adult ALL2,3. Karyotyping reveals recurrent translocations that activate a small number of oncogenes in 25-50% of T-ALLs but with FISH further cryptic abnormalities can be revealed2.

The most common chromosomal rearrangements, found in about 35%2 of T-ALLs, involve the alpha and delta T-cell receptor loci (TRA and TRD) at 14q11.2, the beta TCR locus (TRB) at 7q34 and the gamma TCR (TRG) at 7p14. In most cases the juxtaposition of oncogenes next to the TCR regulatory sequences leads to the deregulated expression of these genes2,4,5.

TRB at 7q34 is rearranged with the genes TLX1 at 10q24, HOX cluster at 7p15, LYL1 at 19p13, TAL2 at 9q32, LCK at 1p34 and NOTCH1 at 9q34 via the t(7;10)(q34;q24); t(7;7)(p15;q34); t(7;19)(q34;p13); t(7;9)(q34;q32); t(1;7)(p34;q34) and t(7;9)(q34;q34) translocations respectively2.

In our hands, Cytocell FISH probes, have proven to be of the highest quality with bright, easy to interpret signals, thus providing confidence in our results. Cytocell’s customer support is outstanding, as their staff are extremely knowledgeable and truly care about their customers and their customers’ needs. Jennie Thurston, Director of Cytogenetics at Carolinas Pathology Group


  1. Rack et al., Blood 1997;90(3):1233-1240
  2. Graux et al., Leukemia 2006;20:1496-1510
  3. Cauwelier et al., Leukemia 2007;21:121-128
  4. Swerdlow et al., (eds,) WHO Classification of Tumours of Haematopoietic and Lymphoid Tissue, Lyon, France, 4th edition, IARC,2017
  5. Gesk et al., Leukemia 2003;17:738-745
  6. Arsham, MS., Barch, MJ. and Lawce HJ. (eds.) (2017) The AGT Cytogenetics Laboratory Manual. New Jersey: John Wiley & Sons Inc.
  7. Mascarello JT, Hirsch B, Kearney HM, et al. Section E9 of the American College of Medical Genetics technical standards and guidelines: fluorescence in situ hybridization. Genet Med. 2011;13(7):667-675.
  8. Wiktor AE, Dyke DLV, Stupca PJ, Ketterling RP, Thorland EC, Shearer BM, Fink SR, Stockero KJ, Majorowicz JR, Dewald GW. Preclinical validation of fluorescence in situ hybridization assays for clinical practice. Genetics in Medicine. 2006;8(1):16–23.

Microscope Images

TCRB (TRB) Breakapart magnified
Area of Interest*


This product is intended to be used on Carnoy’s solution (3:1 methanol/acetic acid) fixed haematological samples.

*Disease information supported by the literature and is not a reflection of the intended purpose of this product.